<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script type="text/javascript">
        var fun1=function () {
            alert("无参函数");
        }
        fun1();

        var fun2=function (a,b) {
            alert("有参函数a=>"+a+"b=>"+b);
        }
        fun2(2,"a");

        var fun3=function (num1,num2) {
            return num1+num2;
        }
        alert(fun3(3,5));
    </script>
</head>
<body>

</body>
</html>